DESCRIPTION (Investigator's Abstract) "This is an application from the Department of Ophthalmology at the University of California, Davis to become a participating Clinical Center in the Ocular Hypertension Treatment Study (OHTS). The principal and co-investigators, along with other members of the UC Davis Department of Ophthalmology, have an established track record participating as clinical centers in large, multi-center studies. UC Davis participated successfully as a clinical center in the Cryo-ROP study and has been selected as the Visual Field Reading Center for both the Optic Neuritis Treatment Trial (ONTT) and for the Ocular Hypertension Treatment Study (OHTS). During the past several years, the principal and co-investigator have been involved in several collaborative studies of perimetry and clinical psychophysics in glaucoma (EY-03424-13). In ongoing and active cooperation with practitioners in private practice, at the local Veterans Administration Outpatient Clinic and at a large multi-clinic HMO (Kaiser Permanente Medical Group), large numbers of ocular hypertensive patients have been successfully recruited and retained for longitudinal psychophysical studies. From January 1, 1992 through December 31, 1992, we have recruited and retained 249 patients for these studies. These patients were recruited using selection criteria similar to those for the OHTS; using the somewhat stricter entry criteria established for OHTS, we estimate that we would have been able to recruit 101 eligible patients during the same twelve month period. This proposal provides complete documentation of the ability of the Department of Ophthalmology at the University of California, Davis to screen large numbers of ocular hypertensive patients and to enroll at least 50 eligible patients over a 24-month period. Documentation is provided of the capabilities of the proposed investigators and their staff for the performance of the study in accord with the details of the OHTS Manual of Procedures, the nature and extent of their commitment to the Ocular Hypertension Treatment Study at the University of California, Davis, and a list of organizations and practitioners in the area who will refer or follow patients screened for enrollment and randomization to treatment in the OHTS clinical trial."